Two and a Half Men: Chocolate Diddlers or My Puppy's Dead (2010)
(TV Episode)
Alan mentions that he recorded an episode of Glee. Later on, when they're watching it, Charlie mentions that "The tall blonde chick in the red tracksuit is really freaking me out", this is a reference to the character Sue Sylvester, played by Jane Lynch who has a recurring role as Charlie's psychiatrist (including in this episode)

The Gallows (2015)
Ryan cites Reese pining over Pfeiffer as a recreation of the Lea Michele and Corey Monteith relationship, he also makes several references to Lea Michele's leading character in reference to Pfeiffer and her dedication to the production of The Gallows.